Method and means for delivering preheated feed water



J. STUMPF Feb. 1,1927.

METHOD ANU MEANS FOR DELIVERING PREHEATED FEED WATER Filed May 27, 1925 5 Sheets-Sheet 1 Feb. 1 1927. 1,616,239

J. STUMPF METHOD AND MEANS FOR DELIVERING PREHEATED FEED WATER Filed May 27, 1925 '5 Sheets-Sheet 2 f iq-- 9 aye/aim";

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' 1,616,239 Feb. 1 1927- J, STUMPF METHOD AND MEANS FOR DELIVERING'PREHEATED FEED WATER Filed May 27, 1925 5 Sheets-Sheet 5 Jaw/ail? Feb. 1 1927.

1,616,239 J. STUMPF METHOD AND MEANS FOR DELIVERING PREHEATED FEED WATER Filed May 27, 1925 5 Sheets-Sheet 4 Feb. 1 1927. 1,616,239

J. STUMPF METHOD AND MEANS FOR DELIVERING PREHEATED FEED WATER Filed May 27, 1925 5 Sheets-Sheet 5 Patented Feb. 1, 1927 I PATENT iorrlc's.

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.npplieation'flled May 27, 1925, Serial No. 33,092, and ii Germany-Hay 31, 1924.

' This invention relates to an improved method for delivering "pre-heated water to boilers or steam generators, more artlcularlv high pressure steam generators y means of injectors, and the invention als embodies a convenient form ofcompound'or multi-stage injector apparatus for carrying the process into efl'ect. The'invention may, be applied to locomotives, loco-mobiles or any form of steam generatingplant.

It has long been recognized that steam in jectors may be used to supply .pre-heated water under pressure to a'boiler,'and the practice hitherto has-been to use one stage in steam and water and to limit the temperature of the feed or the inletwater to the injector so as to ensure safe suction and eflicient injector action by quick condensation of the steam. It has been assumed that in connection with a single stage injector there was a maximum temperature at which the feed Water could be suppliedto the injector and also that there is a maximum temperature, below 212 F., at'which the comingled steam of feed water and condensed injector steam could be delivered from the injector into the boiler, (see; The Steam Engine by Dr. J. Perry 1900, page 615).

As is generally known, thetotal intrinsic energy of the steam entering the ln ector is utilized in part to raise the kinetic-energy 1 of the combined feed water and condensed injector steam and in part to raise the temperature of this combined stream. This kinetic energy is subsequently transformed into pressure energy in the diffuser or tapered delivery pipe of the injector and in this way the feed water is forced into the boiler against the working pressure of the;

fluid therein. 1

I have now found that by compounding injectors in what is analgous to the reverse manner in which prime movers are com pounded, the top limit of feed temperature as hitherto understood canbe considerably exceeded, and I thus recover more heat energy of the working fluid, that is the part of the intrinsic energy of the injector steam which appears in the eo-mingled stream as increase of temperature in the Water delivered. The injector may be arranged intwo or more stages.

In compounding injectors the steam in the first stage is expanded to atmospheric pressure or, if the injector is drawing from the condenser, to the econdenser pressure, and the co-mmgled stream at mcreased pressure and temperature is passed t6 the inlet of the second stage injector. in which the injector steam is expanded down to the inlet water pressure. The limit of temperature of the discharge from the second stage in- "jector is no longer a temperature beneath 212 F. the boiling point at atmospheric pressure,but if the co-mingled stream is at a pressure of 2 atmospheres absolute the temperature would be something less than 250 F. If a third stage is added and the delivery from the second stage is at say 5 atmospheres absolute, the top limiting tem erature will be something less than 300 When applied to a steam power plant, the invention offers advantages additional to these associated immediately with the compoundingv or staking of the injector. As is well known, the auxiliarries, such for exampleas the feed pumps, air pumps or lightmg power plant in a locomotive or other -power un 1ts, donot use the steam'expan sively, or do so only to a small degree. There is thus provided ready-to hand a lurality of sources of supply of steam at di erent pressures. llt is not, therefore, necessary to use high pressure steam in each stage of the injector, but the first stage may use lowpressure steam andeach successive stage may be supplied with a successively higher pres-- sure steam. In this way, the injector stage does not merely'function as a stage in the upgrading of the temperature and pressure of the feed water, but also as a second expansion stage of the incompletely expanded steam from the auxiliaries. I" i I The only losses encountered in the injector are those due to heat radiation and conduction, and those due to friction of the fluid in the passages of the injector. By arranging the injector in stages in the manner set forth, the velocities in.the injector nozzles are those due to the difference in head between the incoming water pressure and the outgoing water pressure. By increasing the pressure in stages the velocity is in all stages.

retained within reasonable limits. When it sumption and consequently the heating ac-- tion.

The invention will be more readily understood from the following description, reference being made to the accompanying-drawin s in which igure 1 is a diagram showing my improved process for supplying feed water to a steam generator by means of a multi-stage injector apparatus.

Figure 2 is a section of a convenient form of multi-stage injector.

Figure 3 is a section taken at right angles to that shown in Figure 2.

Figure 4 is 'a plan view in section on the line AB of Figure 2.

Figure 5 shows a device to draw off exhaust steam from common steam cylinders at higher pressure.

igure 6 shows a'detail of a steam piston suitable herefor.

Figure 7 shows a 3 stage injector, the first stage operated by exhaust steam, the last two stages operated by live steam.

In carrying the invention into effect, steam from a generator G passes by steam mains M to any form of prime mover plant or other apparatus where it is used expansively as indicated in the steam diagram D. Three injectors 1, 1 1 are connectedup, as regards their steam supply, to points in the plant where the boiler steam has been used or partially used expansively. The injector 1 is connected up to a source of steam supply at a low pressure, for example, the exhaust steam from the main engine. This injector may draw water from a cold supply. The steam in this injector will only have a very small range of pressure fall, and the efi'ect will be principally to raise the temperature of the feed to the next injector stage 1 which receives the water at increased pressure, say P. The steam supply to the injector stage 1 will be expanded .down to the pressure P andnot to atmospheric pressure, whereby the kineticenergy of the combined stream of inlet water and condensed steam in 1 is increased by ,an amount corresponding to the pressure difierence between P", the outlet pressure from injector 1 and P the outlet pressure from injector 1. bined stream from 1 is further increased The temperaturebf the com by the condensation of the injector steam 1 and this combined stream at higher pressure and temperature passes to the next stage 1.

Stage 1 may be operated by live steam or by steam of about live steam pressure. This final stage may force the water through pipe N into the boiler with an increased temperature which may be not far below the boiling temperature of the boiler.

It will be understood that any desired number of stages may be interposed. The various sources of supply of steam of different pressure may be obtained from widely different kinds of plant, thus in the case of turbines, the injector steam may be withdrawn from the turbine case at ditierent stages in the expansion of the steam.

The heating action is increased the more exhaust steam and the more head is used for this exhaust steam, which latter may imperil the safe suction action to some extent. Within this limit exhaust steam should be used as much as possible. The same holds true for the interposed stages in which operating steam has been used with a partial drop of pressure in other steam motors.

Also the exhaust steam of the first stage should have some pressure and not too large a head to work against this for ensuring a safe suction. Exhaust steam of some pressure may be secured by the device shown in Figure 5. The two cylinders Z Z of a locomotive are tapped in the middle of the piston s oke. The nozzle-like tap holes D D lead the steam together ejector-like, thus drawing ofi exhaust steam almost entirely expanded by the steam flowing out under some pressure from the other cylinder. The advance in opening the exhaust nozzles may be from 30-40% of the piston stroke. This advance may be decreased by suitable laps 1 at the pistons K K asshown in Figure 6, which may be also omitted entirely. The diffuser (2 will bring up the pressure of the combined exhaust stream in accordance with its kinetic energy. The check valve R is not supposed to work at each stroke but only, if the engine stops or is working slightly. A ressure regulating valve V is kept closed y suificient steam pressure of the exhaust steam receiver A, brought on the closing piston of the valve V by the pipe I). A

spring under this piston will open valve V under insufficient pressure of receiver A and will admit live steam through pipe X, thus maintaining always a certain pressure in the receiver A, which can readily be adspring under this piston will open valve V In modern injectors the action is not readily adjusted-that is to say, there is only a relatively small range between the maximum and minimum deliveries against a given pressure. 1

v on. The gear wheel 9 engages a third' gear;

d which opens or closes steam This is owing to the fact that in injectors as hitherto used, the adjustment has been efiected by throttling the steam. a I

In order to obtain the best action of the injector, the cross section 'of the steam nozzle, the water nozzle and the. diflusersteam and water nozzles, and preferablyv also of the diffuser. I

In multi-stage injectors the various a-djustments might be made separately for each stage, but it is preferable that all the injectors which are arranged in series should be adjustedsimultaneously, and proportionately by a single operating member.

Referring to Figure 2, the invention is here shown applied to a three stage injector adapted to carrying out the process described with reference to the diagram in Figure 1. The inlet water to the first stage of the injector enters by the pipe a and is' drawn by the steam issuing from the nozzle 0 into a contracting and expanding mixer and diffuser p. The steam conveniently from a low pressure source, enters by the'ports e and the water by port 3 both of which are controlled by the c lindricalpart of the slidable nozzle 0'. his cylindrical part is prevented from turning by a notch n, Fig. 3, and internally threaded and is engaged by a thread on the end of a rotatable rod f which passes upwards through a suitable stufiing box 6 and is supported in a bush h carriedby theframe 7. The rod or spindle f has keyed on to it a gear wheel 9 which gears with .the gear wheel gf on a central rod f. The

rod 7' is arranged'similarly t0 the rodand operates the nozzle body d which controls ports e and the steam nozzle 0 andthe water nozzle y of the second injector stage. The spindle f passesthrough a bushing h, and has 'a hand wheel f keyed therewheel 9 fixed on a .spind e F, housed 1n 9. bushing h and adapted in a' manner'similar to the spindle f to control a nozzle body.

ort e for the supply of steam. to the thir steam nozzle 0 and the water ort y of the third injector stage. The itfusers or mixing tubes 32, p, p are suitably designed for the quantities of water passing therethrough and the normal increase in pressure at which they are intended to work.

Tapered control rods k, k project upwardly through the expanding or difiuser part of the mixin tubes for the purpose of controlling the Free area at the most constricted point of the mixing and diffusing tubes as well as the taper ratio of the diffuser. The control memberskflfi k have valves m, m, m fixed on them whichare adapted, when the injector has been started up, to close successively and thus shut off the overflow which escapes by the valve *0 at the bottom lefthand side of Figure 2. It will be seen from Figure 2 that the valves m, m m are at different and increasing heights above their overflow ducts.

B'y moving the rods 70, 70 k simultaneously downwards, the valve m, first closes the overflow from the low pressure injector so that the delivery from this injector then takes place through the ports 0 to the chamber b which is the inlet chamber tothe second injector stage. A further downward movement allows the valve m to close its overflow-duct, whereupon the delivery from the second injector takes place through the ports 0 to the chamber 12 which is the inlet chamber of the third injector stage. A still further downward movement allows the valve m to close its overflow-duct whereupon the discharge from the third injector stage takes place through ports 0 and the delivery valve 6 from the multi-stage in-{ jector.

The downward movement described is eflected by extending the rods 1:,72, k? downwards through the overflow chamber 8 and stufling boxes 9 to be coupled to a spider frame i The spider i is in the form ot a cross,and the arms at right angles to those shown in Figure2 (see Figure 3) v are connected by rods z" to a yoke '71 which engages a thread on-the central spindle f. In this way when the handwheel f is rotated, the nozzle bodies d, d,

(l are simultaneously operated; the steam nozzles c, 0 c and water nozzles .31, 3 are operated to control the steam in ct area and water inlet area for the three injector stages; the constrictions and tapers of the mixing and diffuser tubes are adjusted by the controlling members 10', k

10'' and the overflow valves m',ym m are operated. It Will be understood that after the valves m, m m have closed their over- -fl0w ducts, a further downward movement of the yokei is combined with an upward movement of the above described cylindrical parts thereby increasing the steam "admission area,-the water inlet area and the area of thefconstricted part of the mixing and difiu sertubest If the exhaust steam pressure is" very low and does not ensure safe suction for the first stage, it may be advisable to open the overflow of the second stage first, and afterwards the overflow of the third stage, there being no overflow tor the first stage at all. Then the higher steam pressure of the-second stage will ensure safe starting. 1

This reasoning is more emphasized by the third stage injectors shown in Figure 7. It has three stages in water and two stages in steam, the first stage being operated by exhaust steam and the last two stages by live steam. With an overflow on the two last stages only as described above, the energet-ical live steam will draw the water through the first stage and second stage with all safety, so that any overflow device for the first stage in superfluous and exhaust steam of very low pressure can be used for the first stage. It will be noticed, that both live steam chambers of the last two stages are connected.

The adjustment of the steam nozzle can be furthermore improved by using a needle. If a needle is used like that of the diffuser for decreasing the constricted part of the steam nozle if po:sible with suitable adjustment of the widening of the steam nozzle it would give a better effect.

Having now particularly described and ascertained the nature of my said invention and in what manner the same is to be per.- formed, I declare that what I claim is 1. The method of delivering preheated feedwater, which consists in utilizing the injection action of exhaust steam operating for diflerent stages, the said exhaust steam being of different pressures for the different Stages. I

2. The method of delivering preheated feedwater, which consists in utilizing the injection action of live steam, and exhaust steam operating for different stages, the steam used in some stages being steam that has done work but not expanded down to the exhaustpressure of the cylinders.

3. The method of delivering preheated feedwater, which consists in utilizing the injection action of steam operating for diflerent stages. the live steam operating in some stage or stages and exhaust steam at differ- .ent pressures operating for other stages.

4. The method of delivering preheatedfeedwater, which consists in utilizing the injection action of steam operating for three or more stages, the steam being 0t different pressure i'o each stage.

ferent stages and simultaneously controlling the water inlet for each stage.

6. The method of delivering preheated feedwater, which consists in utilizing the injection action of steam operating for dilierent stages and simultaneously and proportionately controlling the water inlet for each stage.

7. Means for delivering preheated feedwater, comprising a multi-stage injector operating with exhaust steam at difi'erent pressures in different stages.

8. Means for delivering preheated feedwater, comprising a multi-stage injector operating with exhaust steam at different pressures in different stages and live steam in other stage or stages.

9. Means for delivering preheated feedwater, comprising a multi-stage injector and operating means for the simultaneous control of the water inlets of the several stages.

10. Means for delivering preheated feedwater, comprising a multi-stage injector and operating means for the simultaneous control of the steam and water inlets of the several stages.

11. Means for delivering preheated feedwater, comprising a multi-stage injector, and operating means for the simultaneous control of the water inlets and diffusers of the several stages.

12. Means for delivering preheated feedwater, comprising a multi-stage injector, in

combination with a plurality of cylinders and means forbleeding steam, which has already donepartial work, from one cylinder, means for utilizing the injector action of this steam to draw exhaust steam from another cylinder, and means for utilizing the combined steam thus drawn from the diflerentcvlinders for operating one stage of the multi-stage injector.

13. Means for delivering preheated feedwater, comprising a three or more stage in- .jectors and means for delivering thereto different steam pressures for each stage.

14. Means for delivering preheated feedwater, comprising multi-stage injector and means for proportionally adjusting the cross-sections of the steam. water and diffuser nozzles of the several injectors.

15. Means for delivering preheated feed water, comprising a multi-stage injector and means for simultaneously controlhng all the injector stages and for proportionally adjusting the cross-sections of the steam, water and diffuser nozzles of the several injectors.

In testimony whereof I aflix my signature.

J OHANN STUMPF. 

